Exhaust-gas-driven superchargers normally have an actuator, which may be provided in the form or a waste gate actuator, a VTG actuator (VTG=variable turbine geometry) or the like. This supercharger actuator is used to define the proportion of the available exhaust-gas enthalpy that is to be provided in the form of mechanical energy for driving a compressor of the supercharger.
Like other actuators and sensors in an engine system for use in a motor vehicle, the supercharger actuator should also be tested regularly for its proper functioning. The test is usually performed by comparing an actual value and a setpoint value of a charging pressure that is provided by the compressor of the supercharger. Since it is not possible, however, to build up a supercharging pressure in every operating state, a test of the supercharger actuator is not reliably ensured in every operational case.